/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package org.apache.flink.test.recordJobs.sort.tsUtil;

import org.apache.flink.api.common.distributions.DataDistribution;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.types.Key;

/**
 * This class implements the uniform data distribution of the TeraSort benchmark.
 */
public class TeraDistribution implements DataDistribution  {

	private static final long serialVersionUID = 1L;
	private static final int ALPHABETH_SIZE = 95;
	
	@Override
	public Key<?>[] getBucketBoundary(int bucketNum, int totalNumBuckets) {
		final byte[] buf = new byte[TeraKey.KEY_SIZE];
		double threshold = (double) ALPHABETH_SIZE / (double) (totalNumBuckets + 1) * (double) (bucketNum + 1);

		for (int i = 0; i < buf.length; ++i) {
			final int ch = (int) Math.floor(threshold) % ALPHABETH_SIZE;
			buf[i] = (byte) (' ' + ch);

			threshold = threshold - (double) ch;
			threshold = threshold * ALPHABETH_SIZE;
		}

		return new TeraKey[] { new TeraKey(buf, 0) };
	}
	
	@Override
	public int getNumberOfFields() {
		return 1;
	}

	@Override
	public void write(DataOutputView out) {}

	@Override
	public void read(DataInputView in) {}
}
